Hand operated blasting generator



Feb. 20, 1968 B. J. DOUGLASS ET HAND OPERATED BLASTING GENERATOR 2Sheets-Sheet 1 Original Filed March 50, 1964 FIG.2.

Feb. 20, 1968 j DQUGLASS ET AL 3,370,220

HAND OPERATED BLASTING GENERATOR Original Filed March 50, 1964 2Sheets-Sheet 2 76 FIG. 4.

67 21:5: 0 FIG 5. #7

y /48 /28 3 6 W0 v A /60 w K 200 A I J /66 l gz A f 7 A 202 I {/62United States Patent Ofifice 3,370,220 Patented Feb. 20, 1968Continuation of application Ser. No. 355,827,

Mar. 30,

1964. This application June 9, 1967, Ser. No. 645,063

15 Claims. (Cl. 322-40) This application is a continuation ofapplication Serial No. 355,827, filed March..30, 1964, and nowabandoned.

This invention relates to improvements in Control Sys tems.Moreparticularly, this invention relates to improvements in blastingmachines for electric blasting caps.

It is, therefore, an object of the present invention to provide animproved blasting machine for electric blasting caps.

In blasting and demolition operations, it is customary toset theexplosives in place, to afiix electric blasting caps to thoseexplosives, to connect those electric blasting caps in series relation,and then to actuate a blasting machine to fire those electric blastingcaps. The blasting machine is usually located at a point remote from theseries-connected electric caps but it is connected to those caps byelongated leads; and, when that blasting machine is actuated, itcausescurrent to flow through those leads to fire those caps. While blastingmachines can differ from each other, a typical blasting machine includesoutput terminals which are connectable to the elongated leads, agenerator which can be actuated to supply direct current to those outputterminals, and a push-in handle which can actuate that generator. If theoperator pushes the handle of the blasting machine inwardly at asufficiently rapid rate, and if the generator operates in its intendedmanner, the current supplied to the output terminals of the blastingmachine will fire all of the electric blasting caps. However, if theoperator fails to push the handle of the blasting machine inwardlyat asufiiciently rapid rate, the current supplied to the output terminalsmay be just large enough to fire some of the electric blasting caps andnot large enough to fire all of those caps. Also, if the generator doesnot operate in its intended manner, the current supplied to the outputterminals of the blasting machine may be just large enough to fire someofthe electric blasting caps and not large enough to fire all of thosecaps. The firing of less than all of the electric blasting caps isobjectionable because the unfired electric blasting caps, and theexplosives to which they are aifixed, can constitute severe hazards topersons who enter the blasted or demolished area. It would be desirableto provide a blasting machine which could regularly fire all of theelectric blasting caps connected to the output terminals thereof, andwhich would not fire just a few of those electric blasting caps whileleaving the rest of those electric blasting caps unfired. The presentinvention provides such a blasting machine; and it is, therefore, anobject of the present invention to provide a blasting machine which canregularly fire all of the electric blasting caps connected to the outputterminals thereof, and which will not fire just a few of those electricblasting caps while leaving the rest of those electric blasting capsunfired.

The blasting machine provided by the present invention can regularlyfire all of the electric blasting caps connected to the output terminalsthereof, because that blasting machine will apply substantially novoltage to those output terminals until it is ready to apply 21 voltageto those output terminals which is much larger than the minimum voltageneeded to fire any one of those electric blasting caps. This means thatthe electric blasting caps will have substantially no voltage applied tothem until the instant when all of them suddenly receive a voltage whichis much larger than the minimum voltage needed to fire any one of them;and, at that instant, all of those electric blasting caps will respondto that large voltage to fire. As a result, the blasting machineprovided by the present invention can obviate the hazards which unfiredelectric blasting caps, and the explosives to which those caps areafiixed, can constitute. It is, therefore, an object of the presentinvention to provide a blasting machine for electric blasting caps whichapplies substantially no voltage to the output terminals thereof untilit is ready to apply a voltage to those output terminals which is muchlarger than the minimum voltage needed to fire any one of those electricblasting caps.

The blasting machine provided by the present invention has an electriccircuit which includes a voltage-sensitive device; and that deviceremains substantially nonconductive until that blasting machine is readyto apply a voltage to the output terminals thereof which is much largerthan the minimum voltage needed to fire any one of those electricblasting caps. However, as soon as the blasting machine is ready toapply such a voltage to the output terminals thereof, thevoltage-sensitive device will become conductive; and the blastingmachine will then apply the said voltage to the output terminals, andthus to the electric blasting caps. It is, therefore, an object of thepresent invention to provide a blasting machine with an electricalcircuit which includes a voltage-sensitive device that remainssubstantially non-conductive until that blasting machine is ready toapply a voltage to the output terminals thereof which is much largerthan the minimum voltage needed to fire any one of those electricblasting caps.

The blasting machine provided by the present invention utilizes abrushless generator; and such a generator is desirable because it isfree from the electrical noise which develops at the brushes ofgenerators. Such noise is particularly objectionable in a generatorwhich is used in a blasting machine, because that noise can modulate theoutput voltage of that generator and thereby provide transient voltagepeaks which could fire less than all of the electric blasting capsconnected to the output terminals of that blasting machine. By using abrushless generator, the present invention avoids all modulation of theoutput voltage of that generator and thereby prevents firing of lessthan all of the electric blasting caps connected to the output terminalsof that blasting machine. It is, therefore, an object of the presentinvention to provide a blasting machine for electric blasting caps whichuses a brushless generator.

The electrical circuit of the blasting machine provided by the presentinvention includes capacitance; and that capacitance will respond to thecurrent which the generator supplies to it to develop a voltage acrossit. That capacitance will apply that voltage to the voltage-sensitivedevice of the electrical circuit; and, when that voltage rises to apredetermined level, that voltage-sensitive device will becomeconductive. If one actuation of the generator causes the voltage acrossthat capacitance to rise to that predetermined level, thevoltage-sensitive device will immediately become conductive and fire theelectric blasting caps connected to the output terminals of the blastingmachine. However, if one actuation of the generator does not cause thevoltage across that capacitance to rise to that predetermined level,that capacitance will retain enough of the charge thereon to enable asubsequent actuation of the generator to cause the voltage across thatcapacitance to rise to that predetermined level. As a result, firing ofthe electric blasting caps can be attained even if one actuation of thegenerator does not develop sufficient energy to render thevoltage-sensitive device conductive. It is, therefore, an object of thepresent invention to provide a blasting machine with an electricalcircuit that has capacitance which can respond to successive actuationsof the generator of that blasting machine to develop a predeterminedvoltage thereacross.

The capacitance of the electrical circuit of the blasting machinepreferably takes the form of series-connected capacitors and thegenerator is preferably an A.C. generator. In addition, diodesinterconnect those capacitors with the AG. generator in such a way thatthe AC. generator applies a voltage to the capacitance during eachhalf-revolution of the rotor of that generator and a voltage-doublingaction is attained. As a result, the blasting machine provided by thepresent invention can develop and apply a substantial voltage. It is,therefore, an object of the present invention to provide a blastingmachine with capacitance in the form of series-connected capacitors,with an AC. generator, and with diodes which interconnect thosecapacitors with the AC. generator in such a way that the AC. generatorapplies a voltage to the capacitance during each half-revolution of therotor of that generator and a voltage-doubling action is attained.

The preferred form of generator which is used in the blasting machine ofthe present invention has a stationary winding and a rotatable field;and that rotatable field encircles that stationary winding. As a result,that rotatable field has a larger radius than it would have if it wasdisposed within the stationary winding. Further, the greatest proportionof the mass of that rotatable field is concentrated adjacent theperiphery of that rotatable field. Consequently, that rotatable fieldtends to act as a flywheel; and this is desirable, because it enablesthat rotatable field to momentarily rotate with substantiallyundiminished speed after each actuation of the generator. Thatmomentary, substantially undiminished speed is helpful in facilitatingthe firing of electric blasting caps where more than one actuation ofthe generator is required. Further, that momentary, substantiallyundiminished speed is helpful in facilitating the firing of electricblasting caps where the voltage developed within the blasting machineduring the movement of the handle thereof closely approaches, but doesnot reach, the required level; because that momentary, substantiallyundiminished speed can cause the generator to raise the voltage to therequired level. It is, therefore, an object of the present invention toprovide a generator with a rotatable field which encircles a stationarywinding and which has the greatest proportion of the mass thereofconcentrated adjacent the periphery thereof.

The blasting machine provided by the present invention can be made sosmall and so light in weight that it can be carried in the hand orpocket of the operator. This is desirable because it enables thatoperator to carry that blasting machine with him at all times-therebymaking certain that no one can actuate that blasting machine while he 1sworking with, or close to, an electric blasting cap.

It is, therefore, an object of the present invention to provide ablasting machine for electric blasting caps which is small enough andwhich is sufficiently light in weight to be carried in the hand orpocket of the operator.

The blasting machine provided by the present invention is enclosedwithin a water-tight casing. That casing makes it possible to use thatblasting machine in muddy, sandy, and dirty areas. In fact, that casingmakes it possible to use that blasting machine under water. It is,therefore, an object of the present invention to provide a blastingmachine which is enclosed within a water-tight casing.

Other and further objects and advantages of the present invention shouldbecome apparent from an examination of the drawing and accompanyingdescription.

In the drawing and accompanying description a preferred embodiment ofthe present invention is shown and described but it is to be understoodthat the drawing and accompanying description are for the purpose ofillustration only and do not limit the invention and that the inventionwill be defined by the appended claims.

In the drawing, FIG. 1 is a front elevational view of one preferred formof blasting machine that is made in accordance with the principles andteachings of the present invention,

FIG. 2 is a plan view of the blasting machine shown in FIG. 1,

FIG. 3 is a vertical section, on a larger scale, through the middle andlower portions of the blasting machine shown in FIG. 1,

FIG. 4 is a sectional view, on the scale of FIG. 3, through the blastingmachine of FIG. 1, and it is taken along the plane indicated by the line4-4 in FIG. 3,

FIG. 5 is another sectional view, on the scale of FIG. 3, through theblasting machine of FIG. 1, and it is taken along the plane indicated bythe line 5-5 in FIG. 3,

FIG. 6 is a schematic diagram of one preferred form of electricalcircuit for the blasting machine of FIG. 1, and

FIG. 7 is a schematic diagram of a modified form of the electricalcircuit of FIG. 6.

Referring to the drawing in detail, the numeral 20 generally denotes thecasing of one preferred embodiment of blasting machine that is made inaccordance with the principles and teachings of the present invention.That casing is rectangular in elevation, and it is generally rectangularin plan. In the said preferred embodiment of blasting machine providedby the present invention, theheight of the casing 20 is four andone-eighth inches, the width of that casing is two and three-sixteenthinches, and the thickness of that casing is one and one-eighth inches.As a result, that blasting machine can easily be held within the hand ofthe operator, and can also be easily carried in the pocket of theoperator. The casing 20 has an upper compartment 22, a centralcompartment 24, a lower compartment 26, and a closure 28. A gasket 30 ofresilient material is interposed between the closure 28 and the bottomof the lower compartment 26 of the casing 20. Elongated machine screws,not shown, extend upwardly through openings, not shown, in the closure28 and have the threaded shanks thereof seated within threaded openings,not shown, within the upper part of the casing 20. Those machine screwscan be tightened to compress the gasket 30 and thereby provide awater-tight seal between the closure 28 and the lower compartment of thecasing 20. The gasket 30 has the form of a generally rectangular loop;and it largely conforms to the configuration of the bottom face of thelower compartment 26 of the casing 20.

A vertically-directed, cylindrical recess 36 is provided in the upperface of the closure 28; and a smaller-diameter, vertically-directed,cylindrical recess 38 extends downwardly from the bottom of the recess36. An annular shoulder 40 is provided in the closure 28 intermediatethe recesses 36 and 38. A horizontally-directed, cylindrical passage 32is provided in the closure 28; and the righthand end of that passageopens to the right-hand face of the closure 28, while the left-hand endof that passage stops short of the left-hand face of that closure. Thatpassage communicates with, and is generally tangential relative to, therecess 36. A slot 44 is formed in the closure 28 adjacent the left-handportion of the passage 32; and that slot communicates with that passageand also extends to the upper face of the closure 28. A small annularrecess 34 is provided in the closure 28 adjacent the right-hand end ofthe cylindrical passage 32; and that recess opens to that passage.

The numeral 50 denotes a supporting block which is dimensioned to fitsnugly within the lower compartment 26 of the casing 20. Avertically-directed, cylindrical recess 52 is provided in the lower faceof the block 50, and that recess is concentric with the recess 36 in theclosure 28. A further, vertically-directed, cylindrical recess 54 isprovided in the lower face of the block 50; and that recess merges intothe recess 52. As shown particularly by FIG. 3, the recess 54 is not asdeep as the recess 52. A verticallydirected, cylindrical recess 56 isprovided in the upper face of the block 50, and that recess isconcentricwith the recess 52. A vertically-directed, cylindrical recess58 is provided in the upper face of the block 50, and that recess isconcentric with the recess 54; and that recess merges into the recess56. A vertically-directed passage 60 extends between, and communicateswith, the recesses 52 and 56. A vertically-directed passage 62 extendsbetween, and communicates with, the recesses 54 and 58. A slot 63 isformed in the left-hand portion of the block 50, and that slotcommunicates with the upper face, the lower face, and the lefthand faceof that block. That slot communicates with the recess 56, and it'alsocommunicates with a notch 61 in the upper face of the block 50. Ahelical spring 65 is disposed within the notch 61; and one end of thatspring is suitably secured to the block 50, while the end 67 of thatspring extends downwardly through the slots 63 and 44 into the passage32.

The numeral 64 denotes a supporting frame which is dimensioned to fitsnugly within the central compartment 24 of the casing 20. That framehas a vertically-directed, cylindrical recess 66 therein; and thatrecess is concentric with the recess 56 in the block 50. A cylindricalopening 68 is provided in the closed upper end of the recess 66; andvertically-directedhollow spaces 70 and 72 are provided in the frame 64.The casing 20 is preferably made from a sturdy plastic material; and theclosure 28, the block 50, and the frame 64 are preferably made from alight-weight metal such as aluminum.

A supporting disc 74, which has a cylindrical opening at the centerthereof, is dimensioned to fit within the lower end of the cylindricalrecess 66. Preferably, that disc will be dimensioned so it must bepressed into the lower end of that recess. A bushing 76, which hasoppositelydisposed flat faces at the exterior thereof, is pressed withinthe opening 68 in the closed end of the recess 66; and the flat faces ofthat bushing are indicated particularly by FIG. 4. The inner race of ananti-friction bearing 78 is pressed onto the outer surface of thebushing 76; and that inner race will abut the closed end of the recess66.

The outer race of the bearing 78 is disposed within a cylindricalopening in the cup-shaped end 80 of a rotor which is generally denotedby the numeral 81. The largediameter portion of the cup-shaped end 80 ispressed within a sleeve 82; and a cylindrical permanent magnet 84 ispressed within that sleeve and abuts the 'bottom portion of thecup-shaped end 80. That cylindrical permanent magnet can be made fromalnico, from barium ferrite, or from any other suitable material. Acup-shaped end 86 for the rotor 81 is pressed up into the lower end ofthe sleeve 82; and that cup-shaped end has a sleeve-like portion 88which extends downwardly into the cylindrical opening in the disc 74. Anantifriction bearing 90 has the outer race thereof mounted within theopening in the disc 74, and has the inner race thereof telescoped overthe sleeve-like portion 88 on the cup-shaped end 86. The cup-shaped ends80 and 86 will be made from a lightweight, non-magnetic material such asaluminum, but

the sleeve 82 will be made from a magnetic material such as iron orsteel. The bearings 78 and permit the rotor 81 to rotate relative to theframe 64, and thus relative to the casing 20, with a minimum offriction. Because the cup-shaped ends 80 and 86 are made of light-weightmaterial, the greatest proportion of the mass of the rotor 81 isconcentrated adjacent the periphery of that rotor. This is desirable,because it enables that rotor to provide a flywheel effect.

The numeral 92 denotes a laminated core which is generally I-shaped incross section; and the laminations of that core are parallel to themagnetic flux lines developed by the permanent magnet 84. That core ismounted on a support which has a stud-like upper end 96 that is pressedinto the bushing 76; and it has a stud-like end 98 which extends intothe sleeve-like portion 88 on the cup-shaped end 86 of the rotor 81. Theengagement between the stud-like end 98 of the support for the core 92and the sleeve-like portion 88 of the cup-shaped end 86 of the rotor 81will be sufficiently loose to permit ready rotation of the rotor 81relative to the core 92. A two-pole winding 94 is wound on the core 92;and leads 93 and 95 extend upwardly from that winding through passagesdefined by the inner race of bearing. 78 and the flat faces of bushing76-as shown particularly by FIG. 4. The turns of the winding 94 will beneatly held in assembled relation with the core 92 by insulating tape 97or the like. The winding 94, the core 92, and the rotor 81 constitute abrushless A.C. generator.

The numeral 102 denotes a pinion which has a cylindrical extension 100projecting upwardly therefrom. That extension is dimensioned so it canbe pressed into the sleeve-like portion of the cup-shaped member '86 ofthe rotor 81. The engagement between the extension 100 and thesleeve-like portion 88 .will be sufiiciently .tight to enable the pinion102 to effectively serve as part of the rotor 81. Consequently, rotationof the pinion 102 will cause rotation of that rotor.

The numeral 104 denotes a spur gear which has a pinion 106 integrallyformed therewith and which has a shaft-like portion 108. That shaft-likeportion is held by the inner races of anti-friction bearings 110; andthe outer races of those bearings are set within the passage 62 in theblock 50. A retainer 112, such as a snap ring, engages the lower end ofthe shaft-like portion 108 of the spur gear 104 and prevents accidentalseparation of the spur gear from the bearings 110. The spur gear 104 isheld in register with the pinion 102, and the teeth of that spur gearmesh with the teeth of that pinion.

A spur gear 114 is pressed onto the upper end of a sleeve 116 which issupported by the inner race of an anti-friction bearing 118; and theouter race of that hearing is set within the passage 60 in the block 50.The spur gear 114 is disposed above the level of the bearing 118 and isin register with the pinion 106; and the teeth of that spur gear meshwith the teeth of the pinion 106. The

sleeve 116 extends downwardly below the lower face of' the bearing 118;and the lower portion of that sleeve has a cylindrical clutching surfacethereon. A driving member 120 has a cylindrical clutching surface 122thereon; and the diameter of that clutching surface is substantially thesame as the diameter of the clutching surface on the sleeve 116. Thedriving member 120 has a reduced-diameter, upper portion 124 whichextends into the sleeve 116; and the engagement between the sleeve 116and the portion 124 is loose enough to permit ready rotation of thatdriving member relative to that sleeve but is intimate enough tomaintain that driving member and that sleeve in alinement. The drivingmember 120 also has a cylindrical portion 128 at the bottom thereof; andit has a pinion 126 intermediate that cylindrical portion and theclutching surface 122. The portion 128 of the driving member 120 is heldby the inner race of an anti-friction bearing 130; and the outer race ofthat 'hearing is set within the recess 38 in the closure 28. A helicalclutching spring 132 is telescoped over the clutching surface 122 of thedriving member 120 and is also telescoped over the clutching surface onthe sleeve 116. The unstressed diameter of the spring 132 is less thaneither of the diameters of the clutching surfaces of driving member 120and sleeve 116; and hence that spring normally presses against thoseclutching surfaces.

The numeral 134 denotes a plunger which is circular in cross sectionfandthat plunger has a rack on the lefthand portion thereof, as shown byFIG. 5. That plunger is dimensioned to fit within, and to reciprocaterelative to, the cylindrical recess 32 in the closure 28. The end 67 ofthe spring 65 abuts the left-hand end of the plunger 134, and biasesthat plunger for movement toward the extended position shown by FIG. 1.However, that spring can yield to permit that plunger to be moved to,and held in, the retracted position shown by FIG. 5. The teeth of therack on the plunger 134 mesh with the teeth on the pinion 126 of thedriving member 120; and, as that plunger moves within the cylindricalpassage 32, the teeth on that rack will force the pinion 126, and hencethe driving member 120 to rotate. When the plunger 134 is moved from theextended position shown in FIG. 1 to the retracted position shown byFIG. 5, the rack thereon will cause the driving member 120 to rotate inthe counter clockwise direction in FIG. 5. However, when the spring 65moves that plunger from the retracted position shown by FIG. to theextended position shown by FIG. 1, the rack will rotate the drivingmember 120 in the clockwise direction in FIG. 5. An O-ring 136 isdisposed within the annular recess 34 in the closure 28; and that O-ringengages the plunger 134. The engagement between that O-ring and thatplunger is sufficiently intimate to provide a water-tight seal, but isloose enough to permit reciprocation of that plunger relative to thecasing 20.

The numeral 140 denotes a pivot which is secured to the upper portion ofthe casing and a handle 142 is secured to the casing 20 by that pivot.That handle has a concave inner face; and that face engages theright-hand end of the plunger 134. That concave face is desirablebecause it enables any forces, which are applied to that handle andwhich tend to rotate that handle in the clockwise direction in FIG. 1,to keep that handle from shifting laterally away from the plunger 134. Ashallow groove 144 is provided in the outer face of the handle 142adjacent the lower end of that handle; and that groove is parallel tothe pivot 140. The outer face of the handle 142 is knurled to facilitatefirm gripping of that handle.

A folded plate is denoted by the numeral 146, and that plate is foldedto define a groove adjacent the closed end thereof. Screws 158 extendthrough the folded plate 146 and extend into threaded sockets in theclosure 28 to hold that folded plate in assembled relation with thatclosure. The groove adjacent the closed end of the folded plate 146accommodates one side of a loop-like latch 148 and prevents separationof that latch from the closure 28, while permitting rotation of thatlatch relative to that closure. The ouer side of that loop-like latch isdimensioned to fit within the groove 144 in the outer face of the handle142. As indicated by FIGS. 3 and 5, the latch 148 can hold the handle142 in retracted position adjacent the right-hand side of the casing 20;and, as indicated by FIG. 1, that latch can be moved downwardly out ofthe path of the handle 142 to permit that handle to be moved to extendedposition. The groove 144 prevents accidental separation of that latchfrom that handle.

The numeral 160 denotes a threaded output terminal which projectsupwardly from the upper surface of the casing 20, and the numeral 162denotes a similar output terminal. Knurled, cup-shaped nuts 164 and 166are, respectively, threaded onto the output terminals 160 and 162. Anopening 168 is provided in the upper surface of the casing 20intermediate the terminals 160 and 162; and a transparent window 170 isfixed within that opening.

The numeral 172 denotes a lamp which is disposed in the uppercompartment 22 of casing 20* in register with window 170. While a neonlamp is preferred, other lamps could be use-d. A resistor 174 isconnected in series with lamp 172; and that resistor and lamp areconnected across output terminals 160 and 162, as shown by FIG. 6. Aresistor 176 is connected across output terminals 160 and 162, and hencein parallel with series-connected lamp 172 and resistor 174. A biswitch178, which is a bilateral switching diode, has one terminal thereofconnected to output terminal 168, and has the other terminal thereofconnected to the upper terminals of a resistor 186 and a capacitor 182.The lower terminal of resistor 180 is connected to output terminal 162;and the lower terminal of capacitor 182 is connected to the upperterminal of a capacitor 184. The lower terminal of capacitor 184 isconnected to output terminal 162; and this means that capacitors 182 and184 are connected in series with each other and are connected inparallel with resistor 180. A diode 186 has the anode thereof connectedto the lead 93 from winding 34 of the A.C. generator, and the cathode ofthat diode is connected to the upper terminal of capacitor 182. A diode188 has the cathode thereof connected to lead 93 and has the anodethereof connected to the lower terminal of capacitor 184. The lead ofthe A.C. generator is connected to the junction between capacitors 182and 184. Capacitors 182 and 184, lamp 172, .biswitch 1'78, resistors1'74, 176 and 180, and diodes 186 and 188 will preferably be secured toa support which has conductors printed thereon. The said support,capacitors, biswitch, resistors and diodes will be in upper compartment22 of casing 28, but the lower ends of the capacitors will extend intothe hollow spaces 70 and 72.

The right-hand side of the latch 148 will normally be lodged within thegroove 144 in the outer face of the handle 142; and hence that handlewill normally be held close to the casing 20 and will normally hold theplunger 164 in the retracted position shown by FIG. 5. At such time, theend 67 of the spring 65 will strongly urge that plunger toward theextended position shown in FIG. 1; and, in doing so, that spring willhelp prevent accidental freeing of the right-hand side of the latch 148from the groove 144. As a result, the blasting machine can be carried inthe operators hand or pocket without any likelihood of the handle 142being released for movement to extended position.

In using the blasting machine provided by the present invention, theoperator can keep that blasting machine in his pocket while he isengaged in setting the explosives, in afiixing the electric blastingcaps to those explosives, in connecting elongated leads to thoseelectric blasting caps, and in paying out those elongated leads as hewalks from the site of the intended explosion to the site where he willinitiate that explosion. By keeping the blasting machine in his pocket,the operator can have full and complete assurance that a prematurefiring of the electric blasting caps will not be initiated. After theoperator reaches the site where he plans to initiate the explosion, hecan loosen the knurled nuts 164 and 166, connect the ends of theelongated leads to the output terminals 160 and 162, and then tightenthe knurled nuts 164 and 166.

To free the handle 142 for movement to its extended position, theoperator will initially move that handle closer to the casing 20 torelease the right-hand side of the latch 148 from the groove 144; andthereafter that operator will release the handle 142. Thereupon, thespring 65 will force that plunger to move to the extended position shownby FIG. 1.

As that plunger so moves, the rack thereon will coact with the pinion126 on the driving member to rotate that driving member in the clockwisedirection in FIG. 5. That rotation will tend to unwind the clutchingspring 132 which normally presses against the clutching surfaces ofdriving member 120 and of sleeve 116; and that spring will unwindsufficiently to permit that driving member to 9 rotate without rotatingthat sleeve. This means that the plunger 134 will be able to move fromits retracted position to its extended position without causing rotationof the rotor 81 of the A.C. generator.

To fire the electric blasting caps, the operator will place theleft-hand side of the casing 20 adjacent the palm of his hand, will wraphis fingers around the handle 142, and will then firmly and rapidly movethat handle to the retracted position shown by FIG. 5. The plunger 134will simultaneously move to retracted position; and, as that plunger somoves, the rack thereon will rotate the pinion 126 of driving member 120in the counter clockwise direction in FIG. 5. That rotation will causethe clutching surface 122 of that driving member to rotate in thatdirection which enables that clutching surface to tend to wind up theclutching spring 132; and, thereupon, that spring will rotate with thedriving member 120 and force the clutching surface on the sleeve 116 torotate. As the sleeve 116 rotates, it will rotate the spur gear 114; andthat spur gear will rotate the pinion 106 and the spur gear 104. Therotation of spur gear 104 will rotate the pinion 102, and thus rotatethe rotor 81.

The resulting rotation of the magnetic field, provided by thecylindrical magnet 84, relative to the winding 94 on the stationary core92 will generate an alternating voltage in that'winding; and the leads93 and 95 and the diodes 186 and 188 will apply that-voltage to thecapacitors 182 and 184. As a result, whenever the lead 93 in FIG. 6 ispositive relative to the lead 95, current will tend to flow from thewinding 94 through lead 93, diode 186, capacitor 182, and lead 95 tothat winding; and any such flow of current will tend to charge thecapacitor 182 with the upper terminal thereof positive. Also, wheneverthe lead 95 is positive relative to the lead 93, current will tend toflow from the winding 94 through lead 95, capacitor 184, diode 188, andlead 93 to that winding; and any such flow of current will tend tocharge the capacitor 184 with the upper terminal thereof positive. Thismeans that during each revolution of the rotor 81, a voltage will beapplied to the capacitor 182 and a voltage will be applied to thecapacitor 184 by the A.C. generator. Because those capacitors areconnected in series relation, the voltages across those capacitors will:be additive.

The rotor 81 can be rotated quite rapidly-in one preferred embodiment ofthe present invention that rotor has been rotated at rates up to tenthousand revolutions per minute.and the voltages which are applied tothe capacitors 182 and 184 can quickly cause the voltage across thoseseries-connected capacitors to increase. That voltage will be appliedacross resistor 180, and also will be applied across series-connectedbiswitch 178 and resistor 176; and, when that voltage reaches thethreshold level of the biswitch 178, that biswitch will becomeconductive. Until such time as that biswitch becomes conductive,substantially no voltage will be developed across the resistor 176; andhence substantially no voltage will be developed across the outputterminals 160 and 162. However as that biswitch becomes conductive aresulting rush of current through the resistor 176 will develop asubstantial voltage across that resistor 176, and hence across theoutput terminals 160 and 162. In the said preferred embodiment ofblasting machine which is made in accordance with the principles andteachings of the present invention, the root mean square of that voltageis about one hundred and twenty-five volts. Such a voltage is muchgreater than the minimum voltage needed to cause firing of one of theelectric blasting caps; and hence the substantially simultaneous firingof all of the electric blasting caps is assured. As the voltage acrossthe resistor 176 causes firing of the blasting caps, that voltage alsowill cause the neon lamp 172 to become illuminated; and the illuminationof that lamp is very desirable, because it will indicate to the operatorthat an electric charge has been applied to' the elongated leads whichextend to the electric blasting caps.

If an operator squeezes the blasting machine rapidly and firmly, asingle retracting movement of the plunger 134 can regularly fire as manyas twenty series-connected electric blasting caps. In fact, anexperienced operator can, with just one retraction of that plunger, firemore than fifty series-connected electric blasting caps.

In the event the operator does not squeeze the blasting machine withsuflicient rapidity or firmness to effect the firing of the electricblasting caps with just one squeeze, he will release his pressure on thehandle 142 and thereby permit the spring 65 to return the plunger 134 tothe extended position indicated by FIG. 1. The momentum of the rotor 81,and of the gear train which includes pinion 102, spur gear 104, pinion106, and spur gear 114, will keep the rotor 81 rotating at substantialyundiminished speed for several seconds; and, as a result, the sleeve 116and the clutching spring 132 will continue to rotate. As the spring 65moves the plunger 134 from its retracted position to its extendedposition, the rack on that plunger will rotate the driving member in adirection which is opposite to the direction of rotation of the sleeve116. The clutching spring 132 will continue to rotate with the sleeve116; and that spring will unwind sufficiently to keep the rotation ofthe driving member 120 from elfecting any appreciable retardation of thespeed of that sleeve. Once the handle 142 reaches the extended positionshown by FIG. 1, the operator can again squeeze the blasting machine andthereby apply further rotative forces to the rotor 81. The resultingvoltages which will be applied to the capacitors 182 and 184 can, andusually will, increase the voltage across those series-connectedcapacitors to the threshold value of the biswitch 178. Thereupon, theelectric blasting caps will be fired.

The flywheel effect which is provided for the rotor 81, by theconcentration of the largest proportion of the mass of that rotoradjacent the periphery of that rotor, is important; because it enablesthat rotor to rotate at almost undiminished speed for several secondsafter the plunger 134 reaches its fully retracted position. Suchrotation is important because the voltage across the series-connectedcapacitors 182 and 184 frequently does not reach the threshold value ofthe biswitch 178 as the plunger 134 moves to its retracted positionthatvoltage reaching that value immediately after that plunger has reachedits fully retracted position. Such rotation also is important where morethan one squeeze of the blasting machine is required; because suchrotation enables the application of even limited further rotative forcesto the rotor 81 to cause the voltage across the series-connectedcapacitors 1:; and 184 to reach the threshold Value of the biswitch 1 Inthe event one or the other of the leads extending from theseries-connected electric blasting caps to the output terminals and 162becomes broken, the voltage across the capacitors 182 and 184 will notbe applied to those electric blasting caps. That voltage will not,however, be permitted to remain on those capacitors very long; because,in less than one second, the resistors 176 and 180 will reduce thatvoltage below the threshold value of the biswitch 178. This is desirablebecause it will keep the operator from unintentionally firing theelectric blasting caps as the broken lead is subsequently repaired.

In the event the operator of the blasting machine provides only apartial retracting movement of the plunger 134, or provides fullretracting movement of that plunger at a low rate of speed, the voltageacross the series-connected capacitors 182 and 184 may rise to a valuewhich is close to, but slightly below, the threshold value of thebiswitch 178. It would be undesirable to permit that voltage to remainon those capacitors indefinitely; because if the operator of theblasting machine laid that blasting machine down, subsequently pickedthat blasting machine up, and then started moving the handle -142 towardretracted position, the residual voltage on those capacitors could coactwith a small additional voltage to prematurely fire the electricblasting caps. The resistor 180 keeps the voltage on the capacitors 182and 184 from remaining there indefinitely, because that voltage will bedissipated by that resistor in less than eighteen seconds.

The electric circuit of FIG. 6 is extremely rugged and trouble-free.Specifically, that electric circuit can withstand the high current rushwhich occurs when a metal bar is applied directly across the outputterminals 160 and 162 at the moment the biswitch 178 becomes conductive.The ability to withstand that high current rush is due, in part, to thefact that the internal resistances of the capacitors 182 and 184 are inseries with each other and in series with the internal resistance of thebiswitch 178. While the total of those internal resistances is lowenough to permit more-than-enough current to flow through theseries-connected electric blasting caps, connected to the outputterminals 160 and 162, to fire those electric blasting caps, the totalof those resistances is great enough to limit the high rush of currentto a value which is not injurious to the capacitors 182 and 184 or tothe biswitch 178.

The circuit shown in FIG. 6 is very desirable; but other electriccircuits could be used. One such circuit is shown in FIG. 7; and thatcircuit differs from the circuit of FIG. 6 in that a controlledrectifier 200 and a firing circuit therefor have been substituted forthe biswitch 178. That firing circuit includes a Shockley 4-layer diode282 and a series-connected resistor 204; and it will bevoltagesensitive. The controlled rectifier 200 and the Shockley 4- layerdiode 202 will remain substantially non-conductive until the voltageacross that Shockley 4-layer diode rises to a predetermined value.Thereupon, that 4-layer diode will become conductive; and the resultingflow of current through the gate-to-cathode circuit of the controlledrectifier 280 will render that controlled rectifier conductive. At suchtime, the rush of current through resistor 176 will establish thedesired firing voltage across the output terminals 168- and 162.

The biswitch 178 is preferred to the controlled rectifier 200 and afiring circuit therefor; because it reduces the total number ofcomponents required. Also the biswitch 178 has a sharper breakovervoltage characteristic.

The force which is required to rapidly move the handle 142 from itsextended position to its retracted position is well within the grippingcapabilities of almost every adult. For example, a force of only thirtypounds is required to rapidly move that handle from its extendedposition to its retracted position, and such a force is considerablyless than one-half of the force which an average adult male can provide.

The blasting machine provided by the present invention is readilyportable, because it is not only small in size but it is also light inweight. Thus, the total weight of one preferred embodiment of blastingmachine that is made in accordance with the principles and teachings ofthe present invention is less than eight ounces.

Because the blasting machine of the present invention is waterproof aswell as readily portable, that blasting machine can be used in wet,sandy and dirty areas. In fact, that blasting machine can be used underwateras by frogmen doing under-water demolition work.

The lamp 172 is not only helpful in indicating when a voltage has beensupplied to elongated leads connected to the output terminals 160 and162, it is also helpful in showing that the blasting machine is inoperative condition. Specifically, when an operator is checking hisvarious items of equipment at the start of a working day, he can easilycheck his blasting machine by rapidly and firmly squeezing that blastingmachine one or more times until the lamp 172 becomes illumined.Thereafter, throughout that day, each illumining of that lamp will showthat the blasting machine is in operative condition.

The blasting machine provided by the present invention could, of course,be actuated by using two hands to 12 squeeze it. However, that blastingmachine is so compact, so light in weight, and easily actuated that itwill, in almost all instances, be actuated by just one hand.

The blasting machine provided by the present invention is particularlyuseful in the firing of electric blasting caps, electric detonators orelectric squibs. However, that blasting machine can be used for otherpurposes, for example, the firing of flash bulbs. Consequently, whereverthe phrase blasting machine is used in this description and in theappended claims, it will be understood to comprehend a unit whichreadily converts mechanical energy into electrical energy.

The A.C. generator which is part of the blasting machine of the presentinvention could be used in other devices. Such a generator is verydesirable because it does not require brushes or slip rings.Furthermore, that generator is desirable because the field thereof isrotatable and because the largest proportion of the mass of that fieldis concentrated adjacent the periphery thereof. That is additionallydesirable because the winding 94 is on the core 92 and the fieldencircles that core; and hence the total amount of iron in the core issmall and the total distance which the magnetic lines of flux musttraverse in passing through that core is very short. That generator isfurther desirable because the turns of the winding 94 can be easily anddirectly wound onto the core 92.

The blasting machine provided by the present invention can be held indifferent ways. As indicated previously herein, it can be held with thecasing 20 adjacent the operators palm and with the operators fingerswrapped around the handle 142; and that blasting machine can be held inthat way with the output terminals 160 and 162 extending upwardly orextending downwardly. If desired, that blasting machine can be held withthe handle 142 adjacent the operators palm and with the operatorsfingers wrapped around the casing 20; and that blasting machine can beheld in that way with the output terminals 160 and 162 extendingupwardly or extending d0Wnwardly. However that blasting machine is held,it can be held comfortably; because the left-hand face of the easing 20and the outer face of the handle 142 are rounded.

The upper end of the handle 142 projects above the level of the pivot140, and that upper end is formed so it can abut the upper end of thecasing 20, or an abutment thereon, to limit the extent to which thathandle can rotate away from that casing. Such an arrangement isdesirable; because it keeps that handle close enough to that casing tokeep the rack on the plunger 134 from moving out of engagement with thepinion 126 on the driving member 120. Yet, that handle is able to movefar enough to provide ample rotation of that driving member.

The latch 14-8 Will normally hold the handle 142, and hence the plunger134, in retracted position, as shown by FlG. 5. That is desirable,because it will keep rough handhng or dropping of the blasting machinefrom effecting firing of the biswitch 17 8.

The voltage doubler, constituted by the capacitors 182 and 184 and thediodes 186 and 188, is important because it enables an A.C. generator ofsmall size to effect firing of the biswitch 17 8. Specifically, thatvoltage doubler reduces the number of turns needed in the winding 94,and thus reduces the overall size of the core 92-with a consequentreduction in the overall size of the rotor 81. That voltage doubler isadditionally important because it makes it possible to use a small valueof capacitance to provide a large voltage. The resulting smallcapacitance enables the blasting machine to be made small because thecapacitors 182 and 184 can be small. Also, that small capacitancereduces the time constant of the blasting machine, and thereby enablesone or two inward movements of the plunger 134 to fire the biswitch 178.

The biswitch 17 8, the controlled rectifier 200, the Shockley 4-layerdiode 202, and the diodes 186 and 188 are all solid state electricalcomponents. The use of such electrical components is important forseveral reasons. In the first place, such electrical components do notdepend register with an opening,

of the casing 20; and a substantially transparent potting upon theelectrical characteristics of gaseous or liquid components; and hencethe operation of those electrlcal components is not materially affectedby heat, pressure, light or radiation. Further, such electricalcomponents permit substantially full voltage to be supplied to theoutput terminals 160 and 162. Moreover, such electrical componentsreduce the total amount of energy dissipated in the blasting machine,because they have low cut-off levels.

In assembling the blasting machine of the present invention, the bushing76, hearing 78, core 92, rotor 81, bearing 90, disc 74, pinion 102 andits extension 100 will be assembled with the frame 64. Also, a piece ofcardboard, fibre or the like, which has two small openings therein, willhave those openings telescoped over the leads 93 and 95; and then thatpiece will be pressed against the upper face ofthe frame 64.

The capacitors 182 and 184, the biswitch 178, the lamp 172, the diodes186 and 188, the resistors 174, 176 and 180, and the output terminals160 and 162 will be suitably secured to a support therefor. The free endof the' be pressed into position. The clutching spring 132 will betelescoped over the clutching surface on the sleeve 116, and the spring65 will be set in position within notch 61 and slot 63. The reduceddiameter portion 124 of the driving member 120 will be telescoped withinthe sleeve 116,

and the clutching surface '122 will be disposed within the lower portionof the clutching spring 132.

The bearing 130 will be set within recess 38 of closure 28, and theO-ring 136 will he set in recess 34. Thereafter, the plunger 134 will betelescoped into the cylindrical passage 32.

The output terminals 160 and 162, capacitors 182 and 184, the biswitch'178, the diodes 188 and 186, the lamp 172, the resistors 174, 176 and180, and the support therefor will be telescoped upwardly through theopen bottom of the casing 20 until the threaded upper ends of thoseoutput terminals project beyond the top face of the casing 20. The frame64 will then be telescoped upwardly through the open bottom of thecasing 20; and the hollow spaces 70 and 72 therein will accommodate thelower ends of capacitors 182 and 184. Once the frame 64 is set inposition, the block 50 will be telescoped upwardly through the openbottom of casing 20 and abutted against the lower face of that frame.The teeth of pinion 102 and the teeth of spur gear 104 will have beenset so they will smoothly mesh as the block 50 is moved up intoposition. The gasket 30 will then be set in engagement with the lowerend of the casing 20, and the closure 28 will be moved toward thatgasket. The teeth on the rack of plunger 134 will be set to smoothlymesh with the teeth of pinion 126, and the inner race of bearing 130will be alined with the lower end 128 of the driving member 120. Theplunger 123 will be moved far enough to the right to enable theleft-handend thereof to clear the end 67 of spring 65. Machine screws,not shown, will then be telescoped upwardly through openings in theclosure 28 v and seated in threaded openings, not shown, in the casing20.

At this time the nozzle of a potting gun will be set in not shown, inthe upper portion material will then be introduced into the uppercompartmerit 22 of casing 20 and into the hollow spaces 70 and 72 offrame 64. Vent holes, not shown, will be provided in the upper surfaceof the casing 20 adjacent the window 170 and adjacent the outputterminals 160 and 162, and

hence the potting material will fill all voids in the upper compartment22 and in the hollow spaces 70 and 72. That potting material will fullysupport the various elec trical components of the blasting machine andwill also keep water, dirt, sand, or the like from entering the upperportion of the casing 20.

The use of cup-shaped nuts 164 and 166 is particularly desirable wherethe blasting machine is to be used in the ocean or in other bodies ofsalt water. Those nuts will be coated with a layer of insulation so onlythe threads therein will be free of insulation. The portions of theoutput terminals and 162, which will not be completely covered by thenuts 164 and 166, also will be covered with insulation. If only thoseportions of the ends'of the elongated leads, which will be clamped tothe output terminals 160 and 162 and overlain by the nuts 164 and 166,are stripped of insulation, the likelihood of current leaking throughthe salt water will be materially reduced.

Where desired, the blasting machine provided by the present inventioncan be used to fire electric blasting caps .that are connected inparallel. Also where desired, that blasting machine can be used to fireelectric blasting caps that are connected in series-parallel.

The generator provided by the present invention can develop asubstantial output voltage although the plunger 134 has only a shortstroke. For example, in the preferred embodiment of the presentinvention, the generator developed a root mean square voltage of seventyvolts although the plunger moves only about five-eighths of an inch. Thevoltage doubler appropriately multiplies that voltage, and thus assuresprompt firing of the voltagesensitive device.

Whereas the drawing and accompanying description have shown anddescribed a preferred embodiment of the present invention it should beapparent to those skilled in the art that various changes may be made inthe form of the invention without affecting the scope thereof.

What we claim is: 1. A blasting machine which comprises: a generatorthat hasa rotor and a stator and that responds to rotation of said rotorto generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged, whereby said blasting machine can fire loads which can befired only by the application of power to them for appreciable periodsof time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke.

2. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power, manually-operable means to rotate saidrotor of said generator and thereby cause said generator to generatepower,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectively-conductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

said generator being an AC. generator,

said capacitor including a plurality of capacitors,

rectifying means connecting said generator to said plurality ofcapacitors,

said plurality of capacitors and said rectifying means being connectedas a voltage multiplier to supply a rectified and multiplied voltage tosaid solid-state selectively-conductive element.

3. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a change therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-0Elevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

an impedance path connected between said output terminal,

said impedance path completing a firing circuit of predeterminedimpedance for said solid-state selectively-conductive element which willenable said generator and said capacitor to render said solid stateselectively-conductive element conductive, and thereby cause saidsolid-state selectively-conductive element and said capacitor to supplypower to said output terminals, even where the impedance of the loadconnected to said output terminals is too great to enable said load tocomplete a firing circuit for said solid-state selectively-conductiveelement.

4. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said a capacitor thatreceives power generated by said generator and that, responds to saidpower to develop a charge therein and a voltage thereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been renldered conductive, and that has a low cut-offlevel, an

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said'capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low leve-l,"and saidsolid-state selectively-conductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to eifect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue-to generate power after said member has reachedthe end of said stroke,

saidmanually-operable means including a gear train which has some of theshafts thereof mounted in anti-friction bearings and which has aplurality of gears connected to provide large speed multiplication,

whereby said manually-operable means can effect rotation of said rotorat rates of thousands of revolutions per minute, thereby enabling saidgenerator to quickly supply power to said capacitor and to supplysubstantial amounts of power to said capacitor.

5. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator, responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until-thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged, Y

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predeter mined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

a bleed-type resistor connected in parallel with said capacitor,

said bleed-type resistor acting, wheneversaid generator supplies powerto said capacitor but the voltage across said capacitor is not largeenough to render said solid-state selectively-conductive elementconductive, to dissipate energy from said capacitor within a matter ofseconds and thereby reduce the voltage across said capacitor to a valuewell below the threshold level of said solid-state selectivelyconductiveelement.

6. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one ,of said outputterminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor,

and said capacitor responding to said power to develop a charge thereinand a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

said capacitor being constituted by a plurality of capacitors,

said solid-state selectively-conductive element and said plurality ofcapacitors being connected in series relation across said outputterminals,

said plurality of capacitors and said solid-state selectively-conductiveelement having suflicient internal resistance to protect said pluralityof capacitors and said solid-state selectively-conductive elementagainst injury in the event a short is applied across said outputterminals.

7. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross.

a solid-state selectively-conductive element that has a high forwarddrop Whenever it is non-conductive, that has a very low forward dropwhenever it has bee-n rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capaoito-r and one of said outputterminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to lisolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-s-tate selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

sa id solid-state selectively conduotive element remaining conductiveuntil the forward drop thereaoross falls to a lower level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially tullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafiter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

said clutch being a uni-directional clutch that permits said rotor ofsaid generator to continue to rotate at substantially undiminishedspeeds for several seconds after said member has reached the end of saidstroke,

said uni-directional clutch permitting said rotor of said generator tocontinue to rotate in the same direction and at substantiallyundiminished speed while said member of said manually-operable means isready for another stroke,

whereby said manually-operable member can be operated through more thanone stroke to enable said generator to supply additional power to saidcapacitor.

8. A blasting machine which comprises:

agenerator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor ofsaid generator and therbycause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop -acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

an indicator connected across said output terminals to indicate wheneversaid solid-state selectively-conductive element has been renderedconductive.

9. A blasting machine which comprises: 7

a generator that has a rotor and a stator and tha responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cutofflevel, and

output terminals forsaid blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

saidsolid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value, I

said solid-state selectively-conductive element thereafter becomingconductive and connecting saidone terminal of said capacitorto said oneoutput terminal to enable said capacitor to supply power to said outputterminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectively-conductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal,

- andthus continuing to enable said capacitor to supply power to saidoutput terminals, until said capacitor has become substantially fullydischarged.

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time, i

said manually-operable means including a member that p can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

an impedance path connected between said output terminals,

said impedancepath completing a firing circuit of predeterminedimpedance for said solid-state selectively-conductive element which willenable said generator and said capacitor to render said solid-stateselectively-conductive element conductive,

said impedance path facilitating testing of said blasting machine priorto the connecting of said output terminals to a load.

10. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and'thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value, I

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross 1 falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time.

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

an impedance path connected between said output terminals,

said impedance path completing a firing circuit of predeterminedimpedance for said solid-state selectively-conductive element which willenable said generator and said capacitor to render said solid-stateselectively-conductive element conductive,

said impedance path facilitating testing of said blasting machine priorto the connecting of said output terminals to a load, and

an indicator connected across said output terminals to indicate wheneversaid solid-state selectively-conductive element has been renderedconductive.

- 11. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to efifect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

said capacitor being part of a voltage multiplier,

said voltage multiplier enabling said capacitor to have a short timeconstant, thereby minimizing thenumber of revolutions of said rotor ofsaid generator which are needed to fire the load connected to saidoutput terminals. I

12. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power,

manually-operable means to rotate said rotor of said generator andthereby cause said generator to generate power,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said ca pacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to efiect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

, a bleed-type resistor connected in parallel with said capacitor,

said bleed-type resistor acting, whenever said generator supplies powerto said capacitor but the voltage across said capacitor is not largeenough to render said solid-state selectively-conductive elementconductive, to substantially completely discharge said capacitor in lessthan a minute.

13. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power, manually-operable means to rotate saidrotor of said generator and thereby cause said generator to generatepower,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and said solidstate selectively-conductive element thereby continuing to connect saidone terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

an indicator connected across said output terminals to indicate wheneversaid solid-state selectively conductive element has been renderedconductive,

said generator, said capacitor, said solid-state selectively-conductiveelement, and said indicator being enclosed within a housing, and

said indicator being a lamp and being disposed adjacent a window in saidhousing.

14. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power, manually-operable means to rotate saidrotor of said generator and thereby cause said generator to generatepower,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively-conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forward dropwhenever it has been rendered conductive, and that has a low cut-offlevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initiallybeing-non-conductive and thereby isolating said one output terminal fromsaid one terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitorhas become substantially fullydischarged,

whereby said blasting machine can fire loads which can be fired only bythe application of power to them for appreciable periods of time,

said manually-operable means including a member that can be movedthrough a stroke of predetermined length to effect rotation of saidrotor of said generator, said manually-operable means also including aclutch that permits said rotor of said generator to continue to rotateafter said member has reached the end of said stroke, whereby saidgenerator can continue to generate power after said member has reachedthe end of said stroke,

said rotor of said generator having the mass thereof predominatelylocated adjacent the periphery thereof,

the location of the mass of said rotor predominately adjacent theperiphery thereof enabling said rotor of said generator to act as aflywheel and thereby continue to rotate at substantially undiminishedspeed for several seconds after said member has reached the end of saidstroke. I

15. A blasting machine which comprises:

a generator that has a rotor and a stator and that responds to rotationof said rotor to generate power, manually-operable means to rotate saidrotor of said generator and thereby cause said generator to generatepower,

a capacitor that receives power generated by said generator and thatresponds to said power to develop a charge therein and a voltagethereacross,

a solid-state selectively conductive element that has a high forwarddrop whenever it is non-conductive, that has a very low forwarddrop-whenever it has been rendered conductive, and that has a low cutofflevel, and

output terminals for said blasting machine,

said solid-state selectively-conductive element being connected betweenone of the terminals of said capacitor and one of said output terminals,

said generator responding to rotation of said rotor thereof by saidmanually-operable means to generate power and to supply power to saidcapacitor, and said capacitor responding to said power to develop acharge therein and a voltage thereacross,

said solid-state selectively-conductive element initially beingnon-conductive and thereby isolating said one output terminal from saidone terminal of said capacitor, and continuing to isolate said oneoutput terminal from said one terminal of said capacitor until thevoltage across said capacitor attains a predetermined value,

said solid-state selectively-conductive element thereafter becomingconductive and connecting said one terminal of said capacitor to saidone output terminal to enable said capacitor to supply power to saidoutput terminals,

said solid-state selectively-conductive element remaining conductiveuntil the forward drop thereacross falls to a low level, and saidsolid-state selectivelyconductive element thereby continuing to connectsaid one terminal of said capacitor to said output terminal, and thuscontinuing to enable said capacitor to supply power to said outputterminals, until said capacitor has become substantially fullydischarged,

27 28 whereby said blasting machine can fire loads which said generatorbeing a brush-less generator and therecan be fired only by theapplication of power to by generating a substantially noise-free output,th m f r pp ble Periods of time, whereby said solid-state,selectively-conductive element Said manually'operable means including amember that will not be rendered conductive by brush-generated can bemoved through a stroke of predetermined 5 length to eflect rotation ofsaid rotor of said generator, said manually-operable means alsoincluding a clutch that permits said rotor of said generator to continueto rotate after said member has reached the JOHN COUCH Pr'mary Exammer'end of said stroke, whereby said generator can con- 10 H. HUBERFELD,Assistant Examinen tinue to generate power after said member has reachedthe end of said stroke,

noise.

No references cited.

1. A BLASTING MACHINE WHICH COMPRISES: A GENERATOR THAT HAS A ROTOR ANDA STATOR AND THAT RESPONDS TO ROTATION OF SAID ROTOR TO GENERATE POWER,MANUALLY-OPERABLE MEANS TO ROTATE SAID ROTOR OF SAID GENERATOR ANDTHEREBY CAUSE SAID GENERATOR TO GENERATE POWER, A CAPACITOR THATRECEIVES POWER GENERATED BY SAID GENERATOR AND THAT RESPONDS TO SAIDPOWER TO DEVELOP A CHARGE THEREIN AND A VOLTAGE THEREACROSS, ASOLID-STATE SELECTIVELY-CONDUCTIVE ELEMENT THAT HAS A HIGH FORWARD DROPWHENEVER IT IS NON-CONDUCTIVE, THAT HAS A VERY LOW FORWARD DROP WHENEVERIT HAS BEEN RENDERED CONDUCTIVE, AND THAT HAS A LOW CUT-OFF LEVEL, ANDOUTPUT TERMINALS FOR SAID BLASTING MACHINE, SAID SOLID-STATESELECTIVELY-CONDUCTIVE ELEMENT BEING CONNECTED BETWEEN ONE OF THETERMINALS OF SAID CAPACITOR AND ONE OF SAID OUTPUT TERMINALS, SAIDGENERATOR RESPONDING TO ROTATION OF SAID ROTOR THEREOF BY SAIDMANUALLY-OPERABLE MEANS TO GENERATE POWER AND TO SUPPLY POWER TO SAIDCAPACITOR, AND SAID CAPACITOR RESPONDING TO SAID POWER TO DEVELOP ACHARGE THEREIN AND A VOLTAGE THEREACROSS. SAID SOLID-STATESELECTIVELY-CONDUCTIVE ELEMENT INITIALLY BEING NON-CONDUCTIVE ANDTHEREBY ISOLATING SAID ONE OUTPUT TERMINAL FROM SAID ONE TERMINAL OFSAID CAPACITOR, AND CONTINUING TO ISOLATE SAID ONE OUTPUT TERMINAL FROMSAID ONE TERMINAL OF SAID CAPACITOR UNTIL THE VOLTAGE ACROSS SAIDCAPACITOR ATTAINS A PREDETERMINED VALUE, SAID SOLID-STATESELECTIVELY-CONDUCTIVE ELEMENT THEREAFTER BECOMING CONDUCTIVE ANDCONNECTING SAID ONE TERMINAL OF SAID CAPACITOR TO SAID ONE OUTPUTTERMINAL TO ENABLE SAID CAPACITOR TO SUPPLY POWER TO SAID OUTPUTTERMINALS, SAID SOLID-STATE SELECTIVELY-CONDUCTIVE ELEMENT REMAININGCONDUCTIVE UNTIL THE FORWARD DROP THEREACROSS FALLS TO A LOW LEVEL, ANDSAID SOLID-STATE SELECTIVELYCONDUCTIVE ELEMENT THEREBY CONTINUING TOCONNECT SAID ONE TERMINAL OF SAID CAPACITOR TO SAID OUTPUT TERMINAL, ANDTHUS CONTINUING TO ENABLE SAID CAPACITOR TO SUPPLY POWER TO SAID OUTPUTTERMINALS, UNTIL SAID CAPACITOR HAS BECOME SUBSTANTIALLY FULLYDISCHARGED,